Linear DC2048A Demo Manual page 11

connection to a Dust mote (Dc9003a-B)
While the EH_ON signal is low the buck-boost circuit
will consume 750nA from the battery in the sleeping
state. The effects of a pulsed load are shown in Figure 13
at approximately 1850s, where V
EH_ON signal pulses low to high for a brief period of time,
which occurred as a result of the Dust mote radio making
a data transmission.
Figure 14 shows the discharging of V
source is removed and V
IN
threshold causing EH_ON to go low. The supercapacitor
POVOUT
5V/DIV
EH_ON
5V/DIV
V
OUT
1V/DIV
V
IN
200V/DIV
Figure 13. Mide 25W Charging Output Supercapacitor
from 2.5V to 3.6V with Dust Mote Attached
is discharged and the
IN
when the vibration
OUT
drops below the UVLO_FALLING
DC2048A F13
200s/DIV
DEMO MANUAL DC2048A
on V will discharge down to the new target voltage of
OUT
2.5V at which point the buck-boost regulator will turn on
supplying power to the Dust mote. The discharging of
the supercapacitor on V
OUT
for short term loss of the vibration source and extends
the life of the battery.
Figure 15 is the same Dust mote configuration as Figure 12
but without the output supercapacitor. Figure 16 shows the
charging of the output without the supercapacitor attached.
POVOUT
5V/DIV
EH_ON
5V/DIV
V
OUT
1V/DIV
V
IN
200V/DIV
Figure 14. Output Supercapacitor Discharging
When the Vibration Source Is Switched Off
provides an energy source
DC2048A F14
200s/DIV
11
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